Amazon will investigate allegations of discrimination and harassment within its Amazon Web Services unit, following an employee petition that criticized AWS’s culture, The Washington Post reported. More than 550 Amazon workers signed the petition, which calls out AWS for its “underlying culture of systemic discrimination, harassment, bullying, and bias against women and under-represented groups,” the Post reported. The petition further alleges that Amazon’s system to investigate claims of discrimination is “not fair, objective or transparent.”

In May, five women sued Amazon, alleging race and gender discrimination. One of the women, Cindy Warner, worked in the AWS division and had accused a manager of making homophobic comments. When she hired a lawyer, Warner said she was fired in retaliation.

An Amazon spokesperson said in an email to The Verge that the company had conducted a thorough investigation of Warner’s complaints when she made them, and “we have found her allegations to be unsubstantiated.” Warner detailed her allegations in a Medium post on Friday, saying she intended to move forward. “I will pursue my claims as far as I need to in order to show Amazon how wrong management’s actions were,” she wrote. “My wonderful colleagues at AWS will not be intimidated or silenced, either.”

Another incident referenced in the petition was an August 2020 LinkedIn post by former AWS employee Laudon Williams, who said he left the company because he saw instances of what he considered gender discrimination.

Amazon said in its email to The Verge that it does not tolerate discrimination or harassment in any form. The petition was sent to new Amazon CEO Andy Jassy, the former head of AWS, and current AWS chief executive Adam Selipsky, the Post reported.